I don't want to get too caught in the conversation, but for simplifying.
Animals in general tend to be self centered. There are some that marry and have families, there are many that don't, and of course there are one's that just eat their spouse or hatch lings.
Most animals have a shorter lifespan than the average human. They eat they sleep, they mate, they migrate, they live.
Some are tribal, like monkeys, and have a basic sense of morality if it can be called that, but enough so to sometimes kill one of the other members or ostracize it from the group. Some have orders, like our horses kicking the crap out of each other until the leader is decided.
Some animals use tools to achieve a goal.
Humans are an amalgamation of all of this. The largest difference I see between us and other animals, aside from our brains being like powerhouses, is the ability to plan long term. Most animals will consider only for the span of a day, a week, the summer, or winter and not beyond that point. Humans, however, will plan things that will take even centuries to build such as the Pyramids and the Great Wall.
A second possible difference might be the ability to lie, though this might just be due to a breakdown in communication with animals. For the most part, it doesn't seem that animals lie to each other. To humans, such as my dog, if it knows it's done something wrong, it tries to hide the evidence, or be elsewhere where it can feign surprise, but in general lying seems to be a relatively unused aspect that humans tend to use all too much. I'm not saying animals cannot be cunning, sly, and everything else, but they seem relatively 'honest' in their actions and deeds, or at least not trying to hide anything from each other. XD
As for Cushing, I saw the serial in Doctor Who and it felt strange watching the same events played by another actor with small changes made here and there.
The Movie is not the only work that was done with work from the official actor (We have the 2.5 Doctor movie being made that Pertwee worked a bit on), the big difference is that this was considered canon. Somewhere on high, someone gave it a thumbs up. If you ask me, it should never have been made into canon, though I did also like the Tardis interior too. The only reasoning I can see behind what they did was to bring fans of the movie to Nu Who to give it a little extra spur to see if the series would hold. Eccleson only signed up for one year because there was a lot of uncertainty that the series would continue after the first year. A show that is cancelled rarely ever sees the light of day a second time.
Otherwise, a lot of the same basic issues would still exist without the inclusion of the movie. Rather than never seeing the eight change to the ninth, we wouldn't have seen the seventh change into the eighth. That's about it.
Though Russle T. also seemed to like the 'religious' elements of the movie as well and brought in Daleks with a God complex in the very first season, the last thing the series needed.
Si-Fy and Fantasy, that is where my heart lies. To Doctor Who and its 18 years of brilliance, still waiting on the 50 yr anniversary!